The advent of advanced composite materials has enabled the development of pressure vessels of light weight and having very thin walls. Such lightweight vessels made with composite materials are useful in many applications. However, an important disadvantage of such vessels is that the composite materials are easily damaged by impact and do not perform well in high temperature environments.
It will be appreciated that pressure vessels made for many applications, such as the containment of natural gas, for use in automobiles, and the like, must be designed and manufactured in accordance with prescribed standards and, particularly with respect to automobiles and trucks, must meet the strict standards, and comply with the test methods, set by the U.S. Department of Transportation (DOT). For example, such vessels must be resistant to damage and vented during fire so that the vessels do not explode. As indicated above, composite pressure vessels and tanks are, in general, not very damage tolerant. Moreover, damage to such vessels can be difficult to detect during normal inspection procedures, and the damage caused by even a small impact to such a vessel can have a large effect on performance and safety.
Cost is also a factor, particularly in, e.g., the automobile industry, and thus there is a need for an inexpensive way in which to protect pressure vessels and/or to produce pressure vessels providing both impact resistance and fire resistance.
Considering patents of interest here, U.S. Pat. No. 3,969,812 to Beck discloses pressure vessels of the type wherein a thin, lightweight metallic liner is completely overwrapped by a plurality of layers of single-glass filaments.
U.S. Pat. No. 4,699,288 to Mohan discloses a high pressure vessel construction including a plurality of layers of resin impregnated graphite fibers and a plurality of layers of a hybrid of resin impregnated glass and polymer fibers, with the glass and polymer fiber layers alternating with the graphite fiber layers. A layer of elastomer material is joined to the interior surface of the innermost layer of fibers, and a layer of stiff composite material is joined to the interior surface of the elastomer layer.
U.S. Pat. No. 4,767,017 to Logullo, Sr. et al discloses a filament-wound pressure vessel constructed of a rigid composite of an epoxy resin matrix reinforced with continuous filaments of a p-aramid coated with an adhesion modifier.
U.S. Pat. No. 5,177,969 to Schneider discloses a thermochemical actuation method and apparatus wherein a plurality of fins define thin passages that are filled with a material that expands as it changes from a solid to a fluid state.
U.S. Pat. No. 5,287,988 to Murray discloses a metal-lined pressure vessel wherein the outer shell is fabricated of a generally known composite reinforcement made of fiber reinforcing material in a resin matrix. The fiber may be fiber glass, an aramid carbon, graphite, or any other generally known fibrous reinforcing material. The resin matrix may be epoxy, polyester, vinylester, thermoplastic or any other suitable resinous material capable of providing the structural integrity required for the particular application in which the vessel is to be used.
U.S. Pat. No. 5,476,189 to Duvall et al discloses a pressure vessel including a damage mitigating material integrated within the outer shell. The major thickness of the shell is disposed inside the damage mitigating material and a minor thickness of the shell being disposed outside the damage mitigating material. The damage mitigating material or element is a rigid closed cell foam material and may be made of a wide variety of materials including thermoplastics, thermosets, organic or inorganic fibers, rubber, metals, papers, glass, open or closed cell foams, woven or random fiber pads, prefabricated core structures such as honeycombs, and the like. All of the materials, whether restorable or permanently deformable, are physically alterable upon impact by a given exterior force.
U.S. Pat. No. 5,653,358 to Sneddon discloses a multilayer composite pressure vessel with a fitting incorporated in a stem portion thereof. The vessel wall includes a liner, a filament overwrap overwrapping the main portion of the liner for providing structural integrity, the fitting member, and a non-metallic strengthening body localized at and surrounding the stem portion and a portion of the firing member and anchored to the main portion of the pressure vessel between the main portion of the liner and the filament overwrap. The strengthening body includes a body of impregnated filament strengthening material wrapped about the stem portion of the liner and at least a portion of the fitting member. The strengthening body includes a composite of strengthening fibers embedded in a solid matrix of the impregnating material.
U.S. Pat. No. 5,822,838 to Seal et al discloses a high performance, thin metal lined, composite overwrapped pressure vessel. The pressure vessel has multiple layers including a metal liner fabricated from titanium alloy sheet and plate, an adhesive, a composite overwrap which is filament-wound onto the adhesive-covered titanium liner, and a protective coating (epoxy coating) over the overwrap.
U.S. Pat. No. 5,942,070 to Park et al discloses a method for insulating a composite pressure vessel having improved adhesiveness between the insulation and the vessel. The method includes the step of layering up of an uncured carbon fiber fabric/resin prepreg on a mold. An uncured insulating rubber is then layered up and combined with the uncured carbon fiber fabric/resin prepreg by autoclaving.
U.S. Pat. No. 6,190,481 to lida et al discloses a pressure vessel having an outer shell made of a fiber reinforced plastic comprising reinforcing fibers and a resin. The resin impregnated reinforcing fiber bundle is wound around a rotating inner shell at predetermined angles, to thereby form an outer shell.